public class Solution {
    /**
     * @param a: An integer
     * @param b: An integer
     * @return: The sum of a and b 
     */
    public int aplusb(int a, int b) {
        // write your code here
        if (b == 0)
			return a;
		else
			return aplusb(a ^ b, (a & b) << 1);
    }
}